Ponds, Pools and Lochans

3.3 Using the assessment criteria given in Table 8


To assess pond conservation value using the standard criteria given in Table 8 it is necessary to:

  1. obtain a list of plant and/or invertebrate species from the pond, collected using National Pond Survey standard plant and invertebrate survey methods.
  2. use the species lists generated to calculate either (i) the number of species present (ii) numbers of uncommon species (local, nationally uncommon or Red Data Book species) (iii) a Species Rarity Index value for the site.

Calculation of these scores enables the value of the site to be assessed on a national scale. For ease of interpretation, these data can be used to place ponds in one of four conservation value categories: low, moderate, high, very high.

Ponds_fig12.jpg (15550 bytes)

Figure 12. To assess the conservation value of ponds, follow the techniques of the National Pond Survey to obtain a standard list of wetland plants and invertebrates from the pond or pool. Lorne Gill/ SNH

 

Table 8.
Provisional categories for assessing pond conservation value based on wetland plant and macroinvertebrate assemblages
Wetland plants:
Categories for assessing conservation value of ponds (based on the check-list of wetland plants in the National Pond Survey methods booklet).
Low Pond with few wetland plants (8 species). Species Rarity Index score = 1.00 with no local 1, nationally uncommon 2 or Rare 3 species.
Moderate Pond supports a below average number of wetland plant species (9-22 species) and/or below average number of local species (maximum of one local species). Species Rarity Index score = 1.01-1.24.
High Ponds supports an above average number of wetland plant species (23 species) and/or 2 or more local species and/or Species Rarity Index score = 1.25-1.49. No nationally uncommon or Red Data Book species.
Very High Supports one or kmore nationally uncommon or Red Data Book species and/or an exceptionally rich plant assemblage (40 species) and/or Species Rarity Index score = 1.5 or above.
   
Aquatic macroinvertebrates:
Categories for assessing conservation value of ponds (based on a single season, three minute pond-net sample).
Low Pond supports few invertebrate species (0-10) and/or Species Rarity Score = 1.00. No local 1, Nationally Scarce 2 or Red Data Book 3 species present.
Moderate Pond supports below average number of invertebrate species (11-30 species) and/or Species rarity Score = 1.01 - 1.24.
High Pond supports above average number of invertebrate species (31-50 species) and/or Species Rarity Index = 1.25-1.49.
Very High Supports one or more Red Data Book species and/or an exceptionally rich invertebrate assemblage (50 species) and/or Species Rarity Score = 1.50 or above.
1Local: recorded from between 101 and 700 10 x 10 km grid squares in Britain;
2Nationally uncommon: recorded from between 15 and 100 10 x 10 kn grid squares in Britain;
3Rare: listed in the UK Red Data Books.
 
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